An efficient archive securing the integrity of VoIP-based two-party conversations is presented. The solution is based on chains of hashes and continuously chained electronic signatures. Security is concentrated in a single, efficient component, allowing for a detailed analysis.

In this paper we discuss the applicability of GPRS and EGPRS for the transmission of voice packets in an end-toend packet switched scenario. We assume typical Voice over IP (VoIP) applications spanning between a fixed and a mobile terminal. As the transmission delay of the voice packets has most impact on the perceived Quality of Service (QoS), it has been put into focus of our investigations. ...

In interactive voice applications, FEC allows to recover from losses. FEC schemes need to be simple in order to allow interactivity. We study a simple scheme implemented in FreePhone audio tool [High Speed Networking Group, INRIA, Sophia Antipolis, http://www-sop.inria.fr/rodeo/fphone] and RAT: Robust Audio Tool [Multimedia Integrated Conferencing for European Researchers, University College, L...

This thesis presents a concept to achieve non-repudiation for natural language conversations by electronically signing continuous, packet-based, digital voice communication (VoIP). Signing a VoIP-based conversation means to protect the integrity and authenticity of the bidirectional data stream and its temporal sequence which together establish the security context of the communication. The sol...

Acoustic Echo Cancellation (AEC) has become a necessity in today’s conferencing system in order to enhance the audio quality of hands-free communication systems. In recent years, many researchers and manufacturers have developed various AEC algorithms for telecommunication solutions in order to improve the quality of service. Many factors influence the design of an AEC system, such as computati...

Voice communications such as telephony are delay sensitive. Existing voice-over-IP (VoIP) applications transmit voice data in packets of very small size to minimize packetization delay, causing very inefficient use of network bandwidth. This paper proposes a multiplexing scheme for improving the bandwidth efficiency of existing VoIP applications. By installing a multiplexer in an H.323 proxy, v...

From the angle of competition policy, Voice over IP looks like a panacea. It not only brings better service, but it also increases competitive pressure on former telecommunications monopolists. This paper points to the largely overlooked downside. In a pure world of Internet telephony, there would be no charge for individual calls, nor for telephony, as distinct from other services running over...

Increasing number of Internet users forced them to use popular services, television and telephone, to use the Internet as a medium to reach their customers. Organizations are now applying VoIP and MPLS for providing the convergence of voice and data communications over single network infrastructure. VoIP (Voice over Internet Protocol) usage all over their branches, this reduces a huge amount of...

In this research, we propose an architectural solution to implement the voice over IP (VoIP) service in campus environment network. Voice over IP (VoIP) technology has become a discussion issue for this time being. Today, the deployment of this technology on an organization truly can give a great financial benefit over traditional telephony. Therefore, this study is to analyze the VoIP Codec se...